Apparatus for cleaning drip pans of moving stairways



APPARATUS FOR CLEANING DRIP FANS OF' MOVING STAIRWAYS Filed July 1'?. 1947 April 14, 1953 H. E. HANSEN' 5 shets-sneet 1 April 14, 1953 H. E. HANSEN 2,634,850

APPARATUS FOR CLEANING IDRIP FANS OF' MOVING STAIRWAYS Filed July 17, 194'? 3 sheets-sheet 2 a u V il? m `Q N l 4. I l

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ATTORNEY April 14, 1953 H. E. HANSEN 2,634,850 APPARATUS Foa CLEANING DRI? PANs oF MOVING STAIRNAYS Filed July 17, 194'? A 5 Sheets-Sheet 5 g los@ m,"-

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7i. A 7 f mfofygwm ATTORNEY Patented Apr. 14, 1953 APPARATUSEOR CLEANING `DRIP PAN S OF MOVING STAIRWAY'S Hans E. Hansen, Staten Island, N. Y., assignor lto Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 17, 1947, Serial No. 761,623

zo claims. 1

This invention relates to the treatment of surfaces associated with conveyors, and it has particular relation to apparatus for cleaning the drip pans of moving stairways.

Although surfaces may be treated in various ways, as by scraping, abrading, and coating, it will be assumed for the purpose of discussion that the surfaces involved are to be cleaned by brushes. The invention will be described with particular relation to the cleaning of the drip pan of a moving stairway.

The drip pan of a moving stairway in time collects appreciable quantities of oil, grease and debris. Such collections should be removed at regular intervals. in accordance with the prior art, it has been proposed that the entire drip pan of a moving stairway be covered with canvas, and that this canvas be removed at intervals for cleaning purposes. A canvas cover of this type is bulky and difficult to handle.

' In accordance with the invention, a brush unit is disposed for movement by the conveyor means associated with the moving stairway over the surface of the drip pan. Conveniently, such movement may be effected by providing the brush unitwith drive pins, or other suitable drive means, which are engageable in male and female relationship with the conveyor means. In a preferred embodiment of the invention, suitable guide means are provided for guiding the brush unit into position to be engaged by the conveyor means for movement over the surface of the drip pan. After the brush unit has traversed the dri-p pan, the lguide means may guide the brush unit away from the conveyor means for the lpurpose of disengaging the drive pins from the conveyor means.

Preferably, the drive pins are resiliently biased for the pur-pose of preventing damage resulting from incorrect engagement of the drive pins by parts of the conveyor means. Desirably, the drive pins are provided with weak sections adjacent the brush unit to facilitate breakage of the drive pins adjacent the unit if, for some reason, jamming occurs.

After the brush unit has completed a cleaning or sweeping movement, it may be desirable to return the brush unit to its starting position. Such a return may be effected by reversing the conveyor means and establishing the aforesaid male and female engagement between ,parts of the brush unit and the conveyor means. To facilitate the return movement of the brush unit, the brush` may be retracted from the surface of the drip pan during the return movement of the brush unit.

It is, therefore, lan object of the invention to provide 'improved apparatus for treating surfaces associated with conveyors.

It is a further object of the invention to provide improved apparatus for cleaning the drip pan of a `moving stairway.

It is also an object of the invention to provide apparatus for cleaning the drip pan of a movingstairway which includes acleaning unit and guide means for rguiding the cleaning unit into and Out of operative engagement with the conveyor means of the moving stairway for movement over the desired'surface of the drip pan.

It is an additional object of 'the invention to provide a `cleaning unit for a moving stairway having drive pins resiliently biased toward their operative positions, and preferably having weak sections at predetermined points to facilitate breakage at the predetermined points upon application of excessive forces thereto.

It is a still further object of the invention to provide a brush unit for a moving stairway which includes a 'brush yieldably biased toward an operative position, and which has a latch means designed to hold the brush in an inoperative position.

It is another object of the invention to provide an improved method for cleaning the drip pan of a moving stairway.

Other objects of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a view in side elevation, with parts omitted, of a moving stairway embodying the invention;

Fig. 2 is an enlarged view in side elevation, with parts .broken away, showing the rupper end of the moving stairway illustrated in Fig. 1;

Fig. 3 is a view in 4top plan, Awith parts broken away, of a cleaning unit embodying the invention;

Fig. 4 is a view in front elevation of the cleaning unit shown in Fig. 3, with =parts .of a moving stairway added; and

Fig. 5 is a view in side elevation, the portions broken away. of the cleaning unit illustrated in Fig. 3.

Referring to the drawings, Figure 1 shows a movingstairway having a supporting structure I which supports for rotation a lower sprocket 3 and an upper sprocket 4. A pair of endlessh spaced intervals, the chains carry axles 1 for pivotally supporting steps 9. `The chains and the steps comprise parts of a resultant conveyor having an upper section a for conveying passengers, and a lower section 5b for returning the steps to a desired starting point. A con- Ventional balustrade is disposed adjacent the upper section 5a, and has an endless rail |3 which is moved in synchronism with the steps, in a manner well understood in the art.

For moving the steps, the upper sprocket 4 may have a driving motor l5 associated therewith. This motor is connected through suitable speed-reducing gearing i9. to a belt I1 which drives the sprocket 4. Conveniently, the motor I5 may be a three-phase alternating-current motor conected to a suitable source of 'threephase power through a controller 2|. The controller 2| has a button 24a which may be actuated to rotate the sprocket 4 in a clockwise direction as viewed in Fig. 1, a button 2 Ib for actuating the sprocket 4 in a counterclockwise direction as viewed in Fig. 1, and a button 2 Ic for stopping the moving stairway.

For receiving grease, oil and debris, a drip pan 23 is located below, and substantially parallel to, the lower section 5b of the conveyor means. In order to clean the drip pan, a brush unit 25 is provided which includes a carriage 21 and a brush 29 which is pivotally secured to the carriage. The carriage is guided through a predetermined path which is substantially parallel to the drip pan 23 by means of suitable rails 3|. As clearly shown in Fig. 1, the guide rails 3| are substantially parallel to the section 5b; but, at the upper ends, the guide rails depart substanated axle.

tially from the path of the chains 5 and sirnirlarly, at their lower ends, the guide rails depart substantially from the path of the chains about the sprocket 3. The carriage 21 has one or more drive pins 33 projecting therefrom. Each pin is so located that, when it is moved from the position illustrated in Fig. l to the position 33a adjacent the sprocket 4, it will be in a position for engagement by one of the axles 1. For example, if the sprocket 4 is rotated in a clockwise direction as viewed in Fig. 1, the nearest approaching axle 1 will engage the drive pin to urge the carriage 21 toward the lower end of the moving stairway. As the sprocket 4 continues to rotate, the carriage 21 will pass through a position 21h illustrated in dotted lines in Fig. 1, and finally reach a position 21e which is also illustrated in dotted lines. At the position 21o, the carriage has departed from the sprocket' 3 sufciently to provide clearance .between the pin 33 and the axles 1 as they rotate about the sprocket 3. It will be noted that during the transit between the starting position of the carriage and the position 21o, the pin 33 is received between two of the axles in what may be termed a male and female relationship. Consequently, the carriage may be reciprocated in either of two opposite directions, depending on which of the push buttons 2|a or 2lb is actuated.

For example, let it be assumed that the carriage 21 is to be returned from the position 21o to the position illustrated in full lines in Fig. 1. The carriage may be moved manually to the right, as viewed in Fig. 1, until each of the associated drive pins 33 is in a position to be engaged by one of the axles as it is carried around the sprocket 3. If the appropriate button of the controller is actuated to rotate the sprocket 4 in a counterclockwise direction as viewed Yin 4 Fig. 1, one of the axles traveling around the sprocket 3 will engage the drive pin of the carriage 21 to move it toward the position illustrated in full lines in Fig. l. As the drive pin 33 passes through the position illustrated by dotted lines 33a, it will move away from the associated axles to interrupt the engagement between the drive pin and the axles.

The construction of the carriage will be understood from a brief consideration of Figs. 3, 4 and 5. Conveniently, the carriage may be constructed from two steel angles 35 and 31. As shown in Fig. 4, the angle 35 has a horizontal leg 35a and a vertical leg 35h. Similarly, the angle 31 has a horizontal leg 31a and a vertical leg 31b. The legs 35h and 31h have secured thereto, in any suitable manner as by welding, brackets 39 and 4| (Fig. 3) which are rigidly connected to each other by a suitable strap 43. In the embodiment illustrated in the drawings, the strap 43 isl connected to the brackets by suitable machine screws 45.

As previously explained, the carriage 21 Vis designed to be guided along suitable guide rails 3|. The association of the various parts will be understood more clearly by a brief consideration oi Figs. 2 and 4, wherein certain constructional features of a moving stairway are illustrated in somewhat greater detail. It will be recalled that each of the steps 9 is mounted for rotation on a separate axle 1 which is carried by the chains 5. Each of the axles 1 has two rollers 41 which are mounted for rotation with respect to the associ- These rollers cooperate with spaced tracks 49 and 5| to assist in guiding the steps through the desired path. In addition, each of these steps 9 has additional rollers 53 associated therewith which coact with auxiliary tracks 55 and the tracks 49 and 5| to assist in guiding the steps. Further constructional details of moving stairways may be ascertained by reference to the prior art, such as that represented by the Dunlop patents, Nos. 2,060,491 and 2,085,076.

Referring more particularly to Fig. 4, it will be noted that each of the tracks 49 and 5| isprcvided with one of the guide rails 3|. The guide rails 3| may be secured to the tracks 49 and 5| in any suitable manner as by welding. By reference to Figs. 1 and 2, it will be observed that the guide rails 3| extend substantially parallel to the drip pan 23.

In order to guide the carriage 21 along the guide rails 3|, the carriage is provided with four guide jaws 51, 59, 6| and 53 (Fig. 3). Thejaws 51 and 59 are mounted on the angle 35 and the jaws 6| and 63 are mounted on the angle 31 in any suitable marmer. In the specific embodiment herein i1- lustrated, each of the guide jaws is associated with a block 35 which is secured to the associated angle in any suitable manner as by welding. Each guide jaw has a pin 61 projecting through an opening in the associated block 65 and through the leg 351: or 31h of the associated angle. The exposed end of each'of the pins 61 is provided with a washer 69 and a cotter pin 1| for retaining the associated guide jaw in mounted position. With this mounting, each guide jaw is rotatable about the axis of its associated pin 61. Such a construction permits the guide jaws to follow'curves in the guide rails without dimculty. As shown more clearly in Fig. 4, each of the guide jaws has a recess for slidably receiving one of the guide'rails 3|.

It will be recalled that the carriage 21 is provided with drive pins 33 to which forces are apaccesso plied for the purpose of moving the carriage along its associated guide rails. The construction of the guide pins will be apparent from a study of Fig. 4. The legs 35h and 31h of the angles have secured thereto, in any suitable manner as by welding, cups 13 and 15. The cup 13 has a cylindrical bore 13 for the purpose of slidably receiving the pin 33. The pin 33 has a rod 'l1 of reduced diameter projecting therefrom, slidably through an opening 18 in the bottom wall of the cup 13. The exposed end of the rod has a washer 19 and a cotter pin 8| for preventing withdrawal of the drive pin from the associated cup. The cup also contains a helical spring 83 for biasing the associated guide pin 33 in an upward direction as viewed in Fig. 4. With this construction, improper engagement .of the end of the drive pins by parts of the moving stairway results in retraction of the guide pins without injury thereto. As a further safeguard, each of the drive pins may be provided with a weak section E5 adjacent the point of attachment of the drive pin to the carriage `21. If, for any reason, the carriage 21 is jammed, the .drive pins break adjacent the carriage without further injury to the associated apparatus. Both ofthe drive pins are similarly constructed and mounted.

By reference to Figs. .3 and 4, it will be noted that two brushes 29a and 29h are employed to constitute the resultant brush .29. The brushes are secured to a steel angle 31 having a horizontal leg 81a, as viewed in Fig. 5, and a vertical leg 8119. The leg 31h has spacersii for engaging the backs of the brushes 29a and 2919. The spacers 89 may have pins 99a projecting therefrom to enter recesses in the backs of the brushes. The angle 8l' also carries brackets 9|, 33, and 95 (Fig. 4) for the purpose of supporting setscrews 91 in threaded engagement therewith. Each of the setscrews may be advanced into engagement with the backs of the brushes to secure the brushes between the setscrews and the spacers 89 (Figs. 3 and 5). Lock nuts 91a may be provided for the setscrews.

For the purpose of permitting movement of the brushes toward and away from the associated drip pan 23, the brushes are mounted for pivotal movement with respect to the carriage 21. To this end, the angle 81 is secured in any suitable manner to two spaced angle arms 99 and IIJI. The arm 99, as viewed in Fig. 5, has a vertical leg 99a and a horizontal leg 99h. The vertical leg has a pin |83 projecting therethrough and through the leg 35h of the angle 35 for .the purpose of mounting the arm 99 for rotation with respect to the angle 35. As shown in Fig. 3, the pin |03 passes through a spacer |05 and has cotter pins |91 and washers lilla at its ends for retaining the pin |93 in the position illustrated. The arm IIlI similarly is mounted for rotation relative to the angle 31 by means of a pin |03a which is similar to the pin |93. With this construction, the entire brush assembly may be rotated relative to the carriage 21 about the axis of the pins ID3 and Ill3a.

'In order to maintain the brush in operative position despite misalignments of the drip pan and tracks, the pins |03 and 1930i may be allowed limited movements in a vertical direction relative to the arms 99 and IGI or to the angles 35 and 31. For example in Fig. 5 the leg 99a is provided with a vertical slot |94 for receiving the pin |03 and for permitting a limited vertical movement thereof. The pin ||l3a may be associated similarly with the arm IIJ I.

6. `Springs `I 09 (Fig. 4) resilientlybias thebrushes toward the drip pan 23. One of thesprings -IIIS' extends between the leg 35a and the arm 99; whereas, the second of thesprings |09 extends be tween the leg 31a of the angle 31 and the arm IDI.. The mounting of these springs will be apparent from a study of Fig. 5.. In Fig. 5, ya pin .III projects slidably through an vopeniingiin the .-leg .99h of the arm 99. II-5 limit movement of the pin Ain one kdirection relative to 4the arm 39. The .remaining v:end .of the pin projects throughan :opening |.If1;inthe leg 35a of the angle 35 and through a washer' I I9. The end of thepin Ill is upset vor enlarged to limit movement of .thepin .through the washer IIS. It will be noted Itliatthespring |09 ismrounds the ypin :I II and biases the arm .99 Ato gether with the `Vassociated .brushes toward :the drip lpan 23.

Latches I2I are provided for .retaining the brushes in retracted position .relative :to the .drip pan 23. One latch `I2I vis pivotally mounted .on each of the angles 35 and 31 by meansof suit-A able pins |23. If the `brushes are moved upwardly relative to `the associated carriage, the latches engage lips `|25 which are secured tothe angle 81 to retain the brushes :in .retracted :or elevated position, as viewed in Fig. .5. :Thelatohes may be .forced away from itheir associated `'lips to release .the brushes. Upon release vof the brushes, the springs `I 09 yieldably bias the :brushesagainst the -drip pan 23. The pins `have sufncient play in the associated .openingsy of the arms and angles to permit the .aforesaid movement of the brushes.

To facilitate retraction of the brushes, .a fulcrum |21 for a lever is secured tothe bar .4.3. This fulcrum may take the form of a steel plate having an opening I21a therethrough. .A bar o1'4 lever |29 may be inserted through lthe opening I21a for the purpose of engaging the leg 81b oi the angle 81 to raise the brushes from the drip. pan. If it is desired to lock the carriage 21 at one end of the moving stairway, one of the angles 35 or 31 may be provided with an extension I3| having an opening |32 for reception of Va suitable lock. As shown in Fig. 2, the supporting structure I of the moving stairway may be ,provided with a lug |33 having an opening |35 aligned4 may be unlocked and moved from the position. illustrated in Fig. 2 to the left until the drive: pins 33 are in the positions illustrated in dotted. At this point, the latches I2I .may be actuated to release the brushes and permit the brushes to engage the drip pan. The moving lines 33a.

stairway now is energized to rotate the vsprocket 4 in a clockwise direction vas viewed in Fig. 2. .During the resultant motion of the chains, them-st available axle 1 is brought into engagementv withthe drive pins 33 and urges the carriage 21 to-.

ward the left as viewed in Fig. 2. The .motion of the carriage 21 continues until the .carriage passes the sprocket 3 (Fig. l). Since the guide. rails 3| guide the carriage 21 away from the.

sprocket 3 in response to continued motion of the carriage toward the left, the drive pins 331 move out of operative engagement with the associated axle,v as the axle rotates around the sprocket 3. Consequently, the carriage 21 comes A washer :IIB and a cotter :pini

7. toa stop in the position 21c illustrated in dotted lines in Fig. l. OiL'grease and debris swept to the lower end of the moving stairway by the brushes may be removed through suitable service openings.

Although the carriage 21 may be returned to its starting position without raising the brushes from the drip pan 23, preferably the brushes are raised.` For this purpose, the lever |29 is inserted through the opening |21a of the fulcrum (Fig. to raise the brushes until the latches I'2l engage their'associated lips |25. Thereafter, the' latches I 2| retain the brushes in retracted position. The lever 129 is removed and, the moving stairway having been brought to a stop, the carriagel 21 is moved to the right from the position 21c'shown in dotted lines in Fig. l. Such movementof the carriage positions the pins 33 for engagement by one of the axles 1 when the moving stairway is energized to rotate the sprocket 3 in a counterclockwise direction. Continued movement of thestairway then carries the carriage 21 to the upper end of the moving stairway. As the carriage 21 passes the sprocket 4', thedrive pins 33V move out of engagement with the associated axle and the carriage comes to a stop.` The carriage then may be moved into locking position and locked.

Although the invention hasA been described with reference'to certain specific embodiments there- Onnumerous modifications are possible. Therefore, the appended claims have been drafted to cover'all' modifications falling within the spirit and scope of the invention.

I claim as my [invention: 1. In a treating device for treating a surface having spaced guide rails adjacent thereto, a supporting structure, a treating member, means resiliently mounting said treating member on said supporting structure for resiliently biasing the treating member toward an operative position, releasable latch means for retaining said treating member-in an inoperative position to which the treating member is moved against the resiliency of its mounting, and spaced slotted guide jaws secured to the supporting structure for receiving guide rails in the slots thereof and guiding the supporting structure along spaced guide rails associated with a surface to be treated, each of the guide jaws being mounted on the supporting structure for rotation about an axis extending between 'the guide jaws to facilitate tracking of the guide jaws on curved guide rails. 2. In a cleaning device, a supporting structure, spaced slottedguide jaws disposed on opposite sides of the supporting structure, whereby said guide jaws may receive in the slots thereof guide rails for guidingthe supporting structure over a surface to be cleaned in a predetermined path parallel to the vguide rails, a drive element projecting from said Supporting structure adjacent each of said sides in a direction substantially perpendicular to said path, whereby forces may be applied to the drive elements for moving the supporting structure along associated guide rails over a surface to be cleaned, a cleaning member, and means mounting the cleaning member on the supporting structure for movement toward and away from a surface located below the supporting structure, each of the guide jaws being rotatably secured to the supporting structure for rotation about an axis facilitating proper tracking of the guide jaws on curved guide rails.

3. In a moving stairway assembly, a plurality 0f. steps,conveyor means for moving said steps 8 in a predetermined closed path having an upper and a lower section, a carriage engageable with the conveyor means for movement therewith, and guide means for guiding the carriage from a position displaced from the conveyor means to a rst position wherein the conveyor means enga es theV carriage to move it adjacent said lower section to a second position.

4. In a moving stairway assembly, a plurality of steps, conveyor means for moving said steps in a predetermined closed path having an upper and a lower section, a carriage engageable 'with the conveyor means for movement therewith. and guide means for guiding the carriage from a position displaced from the conveyor means to a first position wherein the conveyor means engages the carriage to move it adjacent said lower section to a second position, said guide means including means for guiding the carriage from said second position to a position displaced from the conveyor means.

- 5. In a moving stairway assembly, a plurality of steps, conveyor Vmeans for moving said steps in a predetermined closed path having an upper and a lower section, a carriage engageable with the conveyor means for movement therewith, and guide means for guiding the carriage from a position displaced from the conveyor means to a first position wherein the conveyor means engages the'carriage to move it adjacent said lower section to a second position, said conveyor means being reversible for moving the steps in either of two opposite directions.

6. In a moving stairway assembly, a structure, a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path having a lower return section, the structure having a surface disposed below the return section, and a cleaning unit for cleaning the surface, said cleaning unit, when positioned below the return section and adjacent the surface, being engaged by the conveyor means for movement therewith, said cleaning unit when positioned below the return section and adjacent the surface, having drive means receivable in male and female relationship relative to the conveyor means for forcing the carriage to move over the surface with the conveyor means, and guide means for guiding the cleaning unit from a position displaced from the conveyor means to a rst position establishing the male and female relationship for moving the cleaning unit by the conveyor means over the surface to a second position.

'7. In a moving stairway assembly, a structure,A

a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path having a lower return section, the structure having a surface disposed below the return section, and a cleaning unit for cleaning the surface, said cleaning unit, when positioned below the return section and adjacent the surface, being engaged by the conveyor means for movement therewith said cleaning unit when positioned below the return section and adjacent the surface, having drive means receivable in male and female relationship relative to the conveyor means for forcing the carriage to move over the surface with the conveyor means, and guide means for guid- Y ing the cleaning unit from a position displaced from the conveyor means to a rst position establishing the male and female relationship for moving the cleaning unit by the conveyor means over the surface to a second position, said guide means including means for guiding said carriage away fromy the conveyor means in response to continued movementl of the conveyor means after said carriage has reached the second position.

8. In a moving stairway assembly, a structure,

a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined cl'osed path having an upper section for conveying passengers, said path having a lower return section, the structure having a surface disposed below the return section, and a cleaning unit for cleaning the surface, said cleaning unit, when positioned below the return section and adjacent surface, being engaged by the conveyor means for movement therewith, said cleaning unit when positioned below the return seotion and adjacent the surface, having drive means receivable in male and female relationship relative to the conveyor means for forcing the carriage to move over the surface with the conveyor means, and guide means for guiding the cleaning unit from a position displaced from the conveyor means to a rst position establishing the male and female relationship for moving the cleaning unit by the conveyor means over `the surface to a second position, the cleaning s unitV comprising a cleaning member for engaging the surface, and means for holding the cleaning member in retracted position relative to the surface during movement of the cleaning unit over the surface.

9. In a moving stairway assembly, a structure, a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path having a lower return section, the structure having a surface disposed below the return section, and a cleaning unit for cleaning the surface, said cleaning unit, when positioned below the return section and adjacent surface, being engaged by the conveyor means for movement therewith, said cleaning unit when positioned below the return section and adjacent the surface, having drive means receivable in male and female relationship relative to the conveyor means for forcing the carriage to move over the surface with the conveyor means, and guide means for guiding the cleaning unit from a position displaced from the conveyor means to a iirst position establishing the male and female relationship for moving the cleaning unit by the conveyor means over the surface to a second position, the drive means having a weak section adjacent the cleaning unit whereby initial failure occurs at the weak section.

10. In a moving stairway assembly, a `structure, a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path having a lower return section, the structure having a surface disposed below the return section, and a cleaning unit for cleaning the surface, said cleaning unit, when positioned below the return section and adjacent surface, being engaged by the conveyor means for movement therewith, said cleaning unit when positioned below the return section and adjacent the surface, having drive means receivable in male and female relationship relative to. the conveyor means for forcing the carriage to move over the surface with the conveyor means, and guide means for guiding the cleaning unit from a position displaced from the conveyor means to a rst position establishing the male and female relationship for moving the cleaning unit by the conveyor means over the surface to a second position, the cleaning unit including a carriage, and the drive means including a drive member, means mounting the drive member for movement relative to the carriage in a direction substantially perpendicular to the path of movement of the carriage, and resilient means urging the drive memberrelative to the carriage toward the associated conveyor means.

11. In a moving stairway assembly, a plurality of steps, av supporting structure, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path having a lower return section, a drip pan disposed below and substantially parallel to the return section, reversible means for moving the conveyor means and steps in either of two opposite directions, said conveyor means having spaced parts, a pair of spaced guide rails extending substantially parallel to the return section and projecting beyond the ends of the return section, a carriage having guides engaging the guide rails for constraining the carriage for movement over said drip pan, a cleaning element pivotally associated with the carriage for movement from an operative position engaging the drip pan to a retracted position displaced vfrom the drip pan, means resiliently biasing the cleaning element relative to the carriage into the operative position, releasable means for retaining the cleaning element in retracted position, a driving element projecting from said carriage into the space between said spaced parts, whereby the conveyor means engages the driving element to move the carriage over the drip pan, said guide rails being positioned at each end thereof to guide the carriage from a position wherein the driving element is receivable in said space to a position wherein the driving element is clear of the conveyor means.

'12. In a moving stairway assembly, a plurality of steps, a supporting structure, conveyor means for moving the steps relative to the structure in a predetermined closed path having an upper section for conveying passengers, said path h'aving a lower return section, a drip pan disposed below and substantially parallel to the return section, reversible means for moving the conveyor means and steps in either of two opposite directions, said conveyor means having spaced parts, a pair of spaced guide rails extending substantially parallel to the return section and projecting beyond the ends of the return section, a carriage having guides engaging the guide rails for constraining the carriage for movement over said drip pan, a cleaning element pivotally associated with the carriage lfor movement from an operative position engaging the drip pan to a retracted position displaced from the drip pan, means resiliently biasing the cleaning element relative to the carriage into the operative position, releasable means for retaining the cleaning element in retracted position, a driving element projecting from said carriage into the space between said spaced parts, whereby the conveyor means engages the driving element to move the carriage over the drip pan, said guide rails being positioned at each endl thereof to guide the carriage from a position wherein the driving element is receivable in said space to a position wherein vthe driving element is clear of the conveyor l means, means mounting the driving element for movementl relative to the carriage in a direction perpendicular to the direction of movement of the carriage relative to the supporting structure, said last-named means biasing said driving element relative to the carriage toward the associated conveyor means.

13. In a moving stairway assembly, a plurality of steps, a supporting structure, conveyor means for moving the steps relative to the structure in a predetermined closed path having anupper section for conveying passengers, said path having a lower return section, a drip pan Adisposed below and substantially parallel to the return section, reversible means for moving the conveyor means and steps in either of two opposite directions, said conveyor means having spaced parts, a pair of spaced guide rails extending substantially parallel to the return section and projecting beyond the ends of the return section,

- a carriage having guides engaging the guide rails for constraining the carriage for movement over said drip pan, a cleaning element pivotally asso- I ciated with the carriage for movement from an l ment is receivable in said space to a position wherein the driving element is clear of the conveyor means, the driving element having a weak section adjacent the carriage to facilitatebreakage of the driving element adjacent the carriage when excessive force is applied thereto.

14. The method of cleaning the drip pan below the continuous conveyor of a moving stairway which comprises moving a unit having a cleaning member from a position displaced from the conveyor to a position adjacent a rst end of the drip pan wherein the unit engages the conveyor to be driven by the conveyor, and moving the conveyor in a path to carry the cleaning member over the surface oi' the drip pan toward a second end of the drip pan to sweep the drip pan, raising the cleaning member relative to the remainder of the unit to clear the drip pan, and reversing and returning the conveyor along said path to return the unit by the conveyor to the iirst end of the drip pan.

15. In a conveyor device, a base structure, a conveyor member, means constraining the mem- `ber for movement relative to the structure rthrough a predetermined path, said structure having a surface requiring treatment extending for a substantial distance substantially parallel to the path of said member, a treating member .for treating said surface, and guide means for guiding the treating member through a path which approaches the path of the conveyor mem- Vber at a first predetermined point to eiect en- .established by said guide means diverging from V12 the path oi the conveyor member at a second predetermined point spaced from the rst predetermined point to eiect a release of the treating member by the conveyor member in response to continued movement of the treating member in said first direction.

16. In a conveyor device, a base structure, a conveyor member, means constraining the member for movement relative to the structure through a predetermined path, said structure having a surface requiring treatment extending for a substantial distance substantially parallel to the path of said member, a treating member for treating said surface, and means releasably associating the treating member with the conveyor member for movement of the treating member by the conveyor member over the surface, and means selectively operable for maintaining the treating member in an operative or in an inoperative condition as it moves over said surface.

17. In a conveyor device, a base structure, a conveyor member, means constraining the member for movement relative to the structure through a predetermined path, said structure having a surface requiring treatment extending for a substantial distance substantially parallel to the path of said member, av treating member for treating said surface, means releasably associating the treating member with the conveyor member for movement of the treating member by the conveyor member over the surface, means selectively operable for maintaining the treating member in an operative or in an inoperative condition as it moves over said surface, and means selectively operable for moving said conveyor member through the predetermined path in either of two opposite directions.

18. In a moving stairway assembly, a structure, a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having a section for conveying passengers and a return section, a carriage engageable with the conveyor means for movement thereby over a predetermined path from a first position to a second position, said carriage being releasable for movement from the rst position to a third position out of engagement with the conveyor means, whereby the conveyor means cannot move the carriage while the carriage is in said third position.

19. In a moving stairway assembly. a structure, a plurality of steps, conveyor means for moving the steps relative to the structure in a predetermined closed path having a section for conveying passengers and a return section, a carriage engageable with the conveyor means for movement thereby over a predetermined path from a rst position to a second position, said carriage being releasable for movement from the rst position to a third position out of engagement with the conveyor means, whereby the conveyor means cannot move the carriage while the carriage is in said third position, the structure having a surface disposed substantially parallel and adjacent to said predetermined path, and a treating unit mounted on said carriage for treating said surface in response to movement of the carriage over said predetermined path.

20. In a moving stairway assembly, a structure, a plurality of steps, conveyor means for moving the steps relative to the structure in-a predetermined closed path having asectionfor conveying passengers and a return section, a carriage engageable with theconveyor means for movement thereby over a predetermined path from a first position to a second position, said carriage being releasable for movement from the rst position to a third position out of engagement with the conveyor means, whereby the conveyor means cannot move the carriage while the carriage is in said third position, the structure having a surface disposed substantially parallel and adjacent to said predetermined path, and a treating unit mounted on said carriage for treating said surface in response to movement of the carriage over said predetermined path, the conveyor means being reversible for moving the steps in either of two opposite directions, and means for moving the treating unit relative to the carriage from a location wherein the treating unit engages said surface during movement of the carriage over the predetermined path to a location wherein the treating unit clears said surface during movement of the carriage over said predetermined path, said last-named means being eiective for retaining the treating unit in either of said locations.

HANS E. HANSEN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 196,150 Isaacs Oct. 16, 1877 416,301 Roberts Dec. 3, 1889 457,586 Hagarty Aug. 11, 1891 694,372 Goetz Mar. 4, 1902 932,981 Goi Aug. 31, 1909 1,255,519 Ellis Feb. 5, 1918 2,060,491 Dunlop Nov. 10, 1936 2,236,813 Evans Apr. 1, 1941 FOREIGN PATENTS Number Country Date 198,720 Germany Nov. 15, 1906 

